Pawprints
by attackfishscales
Summary: An affair with Lily causes Sirius more trouble than he anticipated, and Snape's around to enjoy it. Sirius is Harry's father.


**Author's Note:** This story is a sort of dry run for an unconnected Severitus challenge chapter fic that I will write eventually; I wanted to see if I could set an effective story completely inside one of the canon novels with a few of the characters knowing something that the bulk of the characters don't. Oh, and I have used dialogue directly lifted from _Harry Potter and the Order of the Phoenix_, Chapter Twenty-Four (Occlumency) at one point in the story.

* * *

Pawprints

Lily's robe swirled around her as she perched apprehensively on the top step in front of the door of a squat peeling house. The bell had quit working when she was thirteen, so she knocked on the door, listening to the hollow pounding on the other side. Gathering her courage, she knocked a second time, this time tapping in a specific way and order that she had come up with when she was nine, taptap TAP, taptap TAP, TAP TAP tap. She heaved a sigh of relief when she heard the answering knock on the other side, tap TAP tap, tap TAP tap, taptaptap.

"What are you doing?" hissed Sirius, at the bottom and to the side of the steps, nearly invisible in the shadows, "knocking in Morse code?" The baby in his arms woke and started to squall.

The door creaked open to reveal a sallow, haggard wizard. "Lily," he murmured forbiddingly.

She threw her arm around him, glancing back at Sirius and the baby he carried. "Severus." Snape followed her glance into the darkness and scowled at his other visitors. Sirius sent his own scornful look to a spot in the middle of Snape's forehead and the baby stopped screaming to sniffle and then fall silent. "I have a favor to ask."

"Why precisely did you have to bring Black along?" he sneered. "Does Potter send you out with a bodyguard now?"

She flinched, once again glad that James was meeting with Dumbledore, but beckoned Sirius forward anyway. Shrugging the baby up against his shoulder, he stepped into the glow of the cracked house lamp and stood at the bottom of the steps. "The favor's for him too."

"Nothing would induce me to-"

"Oh God!" Lily cut him off. "Sirius and I are having an affair."

Sirius leapt up the steps to put a hand on her shoulder and snarl menacingly at Severus. "Is there any reason you feel the need to tell me this?" Severus questioned dubiously.

She took the baby from Sirius. "Harry's his," her eyes were wide and she began to babble. "It's obvious to anyone who looks for it already, if James had any idea… He's not going to be able to miss it when Harry gets older, he already looks so much like him."

Severus peered at the baby in her arms, then at the man behind her and back again, the resemblance plain even in the rounded infantile features. "Why are you here?" His words were clipped, his teeth bared.

She swallowed, thankful that for once, Sirius stayed quiet. "I need you to brew a glamour potion."

"You're a perfectly adequate potions maker," high praise from him.

"I can't brew a glamour potion at home!" she shrieked. "Even James would get a little suspicious then, and he's at Sirius' flat as often as he's at home anyway, so I can't brew it there either!"

Something cruel darted through Snape's eyes before he inclined his head. "You will pay." His eyes were on Sirius as he spoke. Sirius' jaw jumped as he nodded. "Return in three days."

Lily grabbed Severus' hand, and Black made a move as if to stop her and then caught himself. "Thank you," she whispered, smiling wanly, and Sirius nodded again at her words. As they turned around and walked away, Severus imagined that in his ripped jeans, Black might have been the Muggleborn, and Lily might have been the pureblood from an ancient family, wrapped in her expensive robes. Her hand slipped into his, and the baby slipped back off to sleep on her shoulder.

* * *

In three days time, Sirius Apparated to Spinner's End on his own. He didn't bother tapping in code, not that he knew any should he have wanted to. The door rattled on its hinges even after Snape opened the door, but that might have had something to do with the way he threw it against the inside wall.

Before Sirius even had the chance to speak, Snape retrieved a vial from inside his sleeve and held it out for him to see. Sirius reached for it, his fingers touching the glass before Snape snatched it back. "Last time you were here, I believe I mentioned something about payment."

Sirius gritted his teeth and held back what he wanted to say, which consisted almost entirely of profanities and a certain school nickname of the man in front of him, his hand reaching for his pocket. He pulled put a coin purse, spilling a dozen or so gold Galleons into Snape's waiting palm, crumpling the fabric in fury. "The potion," he managed to spit.

With a cruel smirk, Snape let the vial drop. Sirius almost fell as he scrambled for the vial, catching it in his hand just before it hit the floor. He clutched it to his chest and spun towards the door. "Wait," Snape hissed. Whirling back, Sirius breathed heavily through his nose, not speaking. "Do you think I'm going to let you get away from this short only a few Galleons?"

Growling low in his throat, Sirius faced him. "You already got to watch me beg."

"No," he retorted coldly, "I got to watch you watch Lily beg."

Both men clenched their hands around the handles of their wands, but neither wanted to take the first step and draw theirs. "I already have the potion," Sirius reminded, shaking it lightly and turning toward the door again.

"And I have your secret." Sirius dropped his wand to ball his hand into a fist and only barely caught himself before he slammed it into the potions maker's smug, sneering face.

He laughed instead. "Blackmail, Snivellus? I'd say I didn't think you'd sink that low, but really..."

"Given your position, provoking me is not prudent." Snape's smirk deepened.

Sirius only smirked at him. "You can't risk telling anyone just because I called you a name." He swept his eyes around the cramped house derisively, "You'd be killing your golden goose."

The expression in Snape's hooded eyes grew even crueler. "Do you think I'm doing this for the money, Black?" Sirius shook his head while Snape drove on savagely. "I intend to hold this over you for years, Black. I want to watch you writhe, to know that I could expose you at any moment, and then when I do chose to let this slip…" he bared his teeth. "James Potter's wife and his best friend, carrying on an affair behind his back, and his son isn't his own?" His voice adopted a mock-sympathetic tone and Sirius shivered. "That sort of _betrayal_ would ruin him."

Sirius masked his worry behind a snarl. "You wouldn't. You like Lily too much."

"I like Lily, true, despite her truly lamentable taste," he murmured, gripping his wand, "but more than I hate you?"

Sirius summoned every last bit of his arrogance and leveled it at Snape. "Yes."

There was something ugly in Snape's face, his expression as far from a smile as he could twist it into. "Potter is _scum_," he spat. "There couldn't be anything better for Lily than for him alone!"

"If she wants to leave him, she doesn't need your help," he snapped. "Who do you think she'd be leaving him for anyway?" and if there was anyone Snape thought was as bad as James, it was Sirius.

"I have both of you, you and Potter." He folded his arms across his chest, dangling his wand casually from one hand. He watched Sirius' gaze falling on his wand and snorted softly. "Perhaps I wouldn't be willing to loose your secret, however. Perhaps you want to take that chance."

With a jerk of his head, Sirius swallowed and looked down.

* * *

Though he refused to tell Lily what he and Snape said, she could guess. Over the course of one month, the potion settled into Harry's blood, and his features settled into those of James Potter. The money left Sirius' account promptly at the beginning of each month and then entered Snape' instead.

As the Dark Lord's gaze turned to the Potters and their baby, Severus might have told him that the child was Black's, if Black hadn't defied the Dark Lord the exact same number of times in the exact same ways, _at the exact same times_ as Potter. After Lily had died and Black had been arrested, he might have told Dumbledore, if there had been any point in telling anyone when Black would never find out. Occasionally, a sharp pang of guilt would flash through him, reminding him that if he had told the Dark Lord about the boy's true heritage, Lily might be alive, but she _was_ dead, and there wasn't any point to telling anymore, especially when Black wouldn't know inside his Azkaban cell. Besides, the money that arrived in his account each month despite Black's imprisonment made his scant teaching salary comfortable.

The day the boy arrived in Hogwarts and Sorted into Gryffindor, Severus saw him and wondered fleetingly if he might have overdone the glamour, the resemblance to his step-father was so overpowering. He might have told Dumbledore then, or slipped the antidote into the boy's food and watched his features dissolve, but he didn't need to see the famous Boy-Who-Lived in the papers.

Over the years, Severus got into the habit of taunting the boy about his father, and often it was all he could do not to tell him exactly who his father was and exactly what he had done. As it was, he only referred to the boy's father, and never to the names James Potter or Sirius Black.

When Black escaped from Azkaban, he might again have told Dumbledore, but the Headmaster had a bad habit of telling Potter things for his own good, and the idiot boy would have taken it into his head to meet Lily's murderer and get himself killed as well. The man had an equally bad habit of keeping secrets for others' own good, but Severus didn't trust it. It was too unpredictable.

Severus nearly told Lupin, Potter, and his friends in the shrieking shack before the cretin and his cohorts knocked him unconscious, and afterward, he didn't want to give the boy another reason to cling to the man who murdered his mother.

After the Triwizard Tournament and Dumbledore forced him to accept Black's innocence, he went back to his original plan to torture Black with the prospect of revealing his dirty little secret. Happily, Black didn't want his son to know any more than he had once wanted his best friend to know.

* * *

Severus pressed the cork into the glass vial with a cold smile. He held it up to the light to examine the distinctive iridescent orange streaks in the gold liquid, and then pocketed it. It was flawless, missing only the hair that Lily must have slipped into the vial full she tipped down her son's throat.

When he left for Number Twelve Grimmauld Place, he held a goblet full of Lupin's Wolfsbane potion. Ignoring common courtesy, he Apparated straight into the kitchen, surprising Lupin, who dropped the mug he had been cleaning. It shattered in the sink. Severus sneered at him. "Lupin," he said, setting the Wolfsbane on the table, and then setting the vial of glamour potion beside the goblet.

"What's this?" Lupin asked, picking it up.

'It's for your… friend," he couldn't stop the scowl that spread across his face. "You know which one."

Lupin's expression grew even more suspicious. "What is it?" he repeated.

Severus grimaced. "He knows what it is." He turned to leave, his robe flapping around his feet menacingly, when Black Apparated into the entranceway. They sneered at each other as they passed, and Severus paused near the open kitchen door.

"What the bloody hell was he doing here?" Black's voice reverberated through the house.

Lupin's inaudible murmur soothed Black, whose hackles lowered. Severus waited impatiently as the pair spoke softly. As he sipped his Wolfsbane potion, Lupin picked the vial up from the table and peered at it curiously. With grim satisfaction, Severus watched Black's eyes widen in horror. "He left this too," Lupin told him. "He said you'd know what it was."

As soon as the vial landed in the palm of Black's hand, he threw it as hard as he could at the kitchen wall with a strangled roar. Severus smiled coldly as he Disapparated.

* * *

Just over a month later, Severus gritted his teeth and Apparated to Number Twelve Grimmauld Place with a sharp crack. He handed Black a letter from Dumbledore, outlining his wish that Potter learn Occlumency, feeling no need to repeat the contents. Lupin, upstairs and resting after the full moon, wasn't around to diffuse the situations that were sure to arise when Mrs. Weasley left to fetch Harry into the kitchen. Black dropped the letter onto the table. "I don't like the idea of you picking through my Godson's innermost thoughts," he growled, making it clear as to what he felt were Severus' real intentions.

Severus smirked as he gazed around the kitchen, empty except for the two of them. "Don't be so modest, he's a bit more than your godson."

The letter, which Black had picked up again and started fiddling with as soon as he sat down, fell back onto the table. "I'd have thought you'd have dropped that after _fifteen years_!"

"Don't be ridiculous, Black," he smirked even more broadly. "You knew exactly what you were getting into when you came to me fifteen and a half years ago."

"I don't care anymore," he hissed fiercely. "Tell Harry then." See if he believes you, Severus heard, even if Black didn't say it out loud.

"I wouldn't be telling only Potter," his limp hair fell into his face. "I'd tell the Daily Prophet, Witch Weekly, the boy's aunt and uncle; I'd make this into a media circus. The two of you would have the privilege of seeing just what the press and his family make of him being the son of a convicted murderer." He listened triumphantly to the rumble in the bottom of Black's throat and pressed on, "Or I could just slip a revealing elixir into his evening meal tomorrow and leave everyone to draw their own conclusions." The skin stretched around Black's protruding features took on a heartwarming pallor, and Severus sat back in his chair satisfied. As Black stuttered, however, he couldn't help leaning forward with one last dig. "Given how much the boy resembles Potter now, no doubt his resemblance to you would be similarly… unmistakable."

Black spat onto Severus' boot, and his smirk dissolved into a venomous sneer.

When Potter slunk into the kitchen, Severus snapped at him to sit down. "You know," Black leaned back in his chair to gaze at the grease spotted ceiling, "I think I'd prefer it if you didn't give orders here, Snape. It's my house, you see."

Severus flushed, furious that Black would bluster and use Potter's as a shield against certain forms of retaliation. At least the boy looked suitably apprehensive as he sank into a seat next to his father. "I was supposed to see you alone, Potter," he said contemptuously, "but Black-"

"I'm his godfather," Black said, his voice rising with every word. Severus watched his neck tense and bob as he spoke, his lip curling. A wicked thought glimmered in his mind. Perhaps Black wasn't using Potter as a shield. Perhaps he merely wanted to _impress_ Potter.

Perversely, Severus lowered his voice dangerously, forcing the other two to lean in to hear him. "I am here on Dumbledore's orders," he paused, before stabbing that possible weakness, "but by all means stay, Black, I know you like to feel… involved."

"What's that supposed to mean?" As Black's gaze snapped back to him, the legs of his chair fell to the floor with a sharp bang, and Severus let out a breath with the knowledge that he had guessed right.

"Merely that I am sure you must feel- ah- frustrated by the fact that you can do nothing _useful_ for the order." When Black's features colored, Severus's features contorted with scorn, which he didn't bother to hide when he turned to face Potter. "The headmaster has sent me to tell you, Potter, that it is his wish for you to study Occlumency this term."

"Study what?" the boy asked blankly, and Severus' lip curled further.

"Occlumency, Potter. The magical defense of the mind against external penetration. An obscure branch of magic, but a highly useful one."

His already poor opinion of the boy's intelligence lowered still further when he burst out, "Why do I have to study Occlu- thing?"

"Because the headmaster thinks it a good idea," not bothering to hide his condescension, he reveled in the way the pair facing him bristled as one. "You will receive private lessons once a week, but you will not tell anybody what you're doing, least of all Dolores Umbridge. You understand?"

"Yes," Potter said. Severus doubted it. "Who's going to be teaching me?"

He raised an eyebrow, expression heavy with distaste, "I am." As he spoke, the boy's color bled away, and he twisted around to his godfather, on the edge of begging.

"Why can't Dumbledore teach Harry?" demanded Black leaning forward threateningly, his fingers curling into fists.

"I suppose because it is a headmaster's privilege to delegate less enjoyable tasks," he shot back sleekly, though he hoped to wring what pleasure he could from the misery of the two in front of him. "I assure you I did not beg for the job." He rose jerkily and paused. "I will expect you at six o'clock on Monday evening, Potter. My office. If anybody asks, you're taking Remedial Potions. Nobody who has seen you in my classes could deny you need them." With that last parting shot, he spun around and stalked towards the door.

"Wait a moment," Black ordered without rising, his back rigid in his chair.

He whirled back, face twisting, "I am in rather a hurry, Black…" he lied, "unlike you, I do not have unlimited leisure time…"

Black rose to the bate beautifully, shooting to his feet and closing his fist over the handle of his wand. "I'll get to the point then," he snapped. "If I hear you're using these lessons to give Harry a hard time, you'll have me to answer to."

"How touching," Severus found that the best way to deal with a schoolyard bully was to remind him how little power he had. "But surely you have noticed that Potter is very like his father?"

"Yes I have," Black had the gall to sound proud.

"Well then, you'll know he's so arrogant that criticism simply bounces off him," he said, twisting the knife deeper.

Black shoved the chair aside as he marched around the table and jabbed his wand to point it right between Severus's eyes. Their eyes swept across each other, the hatred palpable between them.

"Sirius!" Potter reached up as if to grab Black's arm, but he didn't notice.

"I've warned you, _Snivellus_," Black spat, his face so close to Severus that spittle landed on his nose, "I don't care if Dumbledore thinks you've reformed, I know better-"

"Oh, but why don't you tell him so?" his voice dropped until it was almost inaudible. "Or are you afraid he might not take the advice of a man who has been hiding inside his mother's house for six months very seriously?"

"Tell me, how is Lucius Malfoy these days?" Black drawled, too livid to be properly sarcastic. "I expect he's delighted his lapdog's working at Hogwarts, isn't he?"

"Speaking of dogs," Severus murmured, "did you know that Lucius Malfoy recognized you last time you risked a little jaunt outside? Clever idea, Black, getting yourself seen on a safe station platform…" he waited a moment for dramatic effect, "gave you a cast-iron excuse not to leave your hidey-hole in the future, didn't it?"

Black raised the tip of his wand, his hand shaking with rage.

"NO!" Potter shouted, leaping over the kitchen table, landing in between them, hands spread to keep them apart, "Sirius, don't-"

"Are you calling me a coward?" Black bellowed, trying to push Potter out of the way, but the boy rocked back on his heels and stood his ground, unaware of how appropriate his placement between the two of them was.

"Why, yes, I suppose I am," he said gleefully.

"Harry- get- out- of- it!" Black ground out with exasperation, driving Potter back with the hand not holding his wand.

Before they could do any more than size each other up, the door burst open and the Weasley family and Granger pushed through it en masse, Arthur Weasley clad in a mackintosh and pajamas. "Cured!" he told them cheerfully, "completely cured!" Then suddenly, he and the rest seemed to realize what they were looking at, Severus and Black facing each other, their wands outstretched, and Potter between them trying to keep them from hexing each other.

* * *

With Black's death, Severus found himself in possession of a substantial sum of money and a cryptic message saying just that Potter, who had inherited the remainder of Black's estate, would be sure to see monthly payments extracted from his portion. Dumbledore, who executed Black's will raised an eyebrow as he handed Severus the Galleons, but when he queried after what they were for, Severus replied only, "Blackmail," savoring the way the word felt on his tongue and how appropriate it was given the name of the man whose secret he concealed, and refused to say any more.

In truth, he didn't know why Black bothered. Once he was dead, Severus had no reason to divulge his secret. Potter wouldn't have been particularly horrified to find that Black and not the elder Potter was his father; the two had always gotten along disgustingly well. Besides which, he didn't need to give the boy another reason to trail around the school looking forlorn about the man's death.

When it came down to the end, and he felt the need to justify himself to Potter and show him what needed to be done, he hadn't let the memory of the summer's evening almost eighteen years before slip past his ears with the others. Of course, after that, he wasn't in any position to reveal anything.


End file.
